Camming device for climbing or use thereof

ABSTRACT

A camming device is provided that has a superior range of operation, is lighter and has lower internal compressive forces. The improvement is a result of using a composition having a co-efficient of friction ranging between 0.35-0.55 affixed to the contact area, for example, a semi-metallic composition. An improved method of fall protection is also provided, as is a method of manufacture.

RELATED APPLICATIONS

This application claims priority to U.S. provisional patent application Ser. No. 60/672569, filed 18 Feb., 2005, entitled Camming Device for Climbing and Use Thereof.

FIELD OF THE INVENTION

This invention is related to devices to assist rock and mountain climbers. Specifically, this invention is a climbing cam that has a superior range as a result of long-lasting high friction material on the face of the cam and low weight “rope” stem.

BACKGROUND OF THE INVENTION

Mountain climbing is a sport of limits. Rock climbers are relentlessly striving to push these limits by enduring personal physical pain, improving technical climbing abilities and inventing innovative technical gear. Lowering weight and increasing strength of climbing gear are the fundamental improvements that are required to extend the limits of climbable routes. Fall protection is the key aspect to this. Fall protection is what a climber uses to secure himself/herself to the rock face while climbing. In the event of a fall, the “fall protection” will stop the climber falling to their death. Fall protection requires a delicate balance between strength requirements and weight conservation.

A climbing camming device (cam or friend) is one type of device used as fall protection by mountain climbers. Primarily used for crack climbing, the cam is inserted into a crack and the safety rope is fixed to the stem loop. Friction from the rock/aluminum lobe interface and the outward normal force generated by the unique cam lobe shape holds the camming device in the crack when loaded by a fall. Camming devices have revolutionized rock climbing because climbing routes with parallel crack systems can now be protected. Also, unlike pitons or other forms of permanent protection, camming devices do not damage the rock and are easily placed and removed.

Camming devices range in size and consist of two to four aluminum spring-loaded cams (lobes) with a logarithmic spiral contact shape. These cams are mounted onto a stainless steel axle and connected to a 3/16″ 302 stainless steel aircraft cable stem. The climbing rope is fixed to the stem with standard nylon webbing and when weighted the downward force on the stem forces the cams to spread and hold into the rock.

When traveling to and from the climbing site, and while on a climb, a climber must carry a full range of camming devices in order to accommodate various crack sizes. For this reason, it is necessary to consider the weight of the rack of camming devices. Various approaches have been taken to reduce the weight. Firstly, aluminum is used as much as possible as it is lighter than steel. Second, the weight has been further reduced by introducing apertures into the camming devices. As the number of axles used also affects the weight of a camming device, weight can be reduced by using single axle camming devices, rather than the heavier double axle camming devices. These approaches reduce the weight of each camming devices, and therefore, the weight of the rack.

An alternative approach to lightening the weight of the rack, is to reduce the number of camming devices that needed to be carried. This can be done by increasing the range a given camming device. Expansion range is the maximum minus the minimum crevice size a camming device will tolerate. Double axle camming devices have more expansion range than single axle camming devices, hence fewer camming devices need to be carried. However, this gain may be offset by the increased weight of the double axle camming devices over that of the single axle camming devices.

The problem for climbers is how to reduce the weight required for climbing while remaining within an acceptable safety margin, based on fit of the camming device in the crack and strength of the camming device. It is an object of the present invention to overcome the deficiencies of the prior art.

SUMMARY OF THE INVENTION

An improved camming device is provided that has a superior range of operation, is lighter and has lower internal compressive forces. A camming device is for use as protection in cracks during rock climbing, and comprises at least one pair of lobes, one axle per pair of lobes, a stem, a loop and a release mechanism. The lobes comprise: a face having a contact area; an inside edge; an apical end; and a basal end, to define an inner surface and an outer surface. The improvement comprises a semi-metallic composition comprising at least one metal affixed to the contact area.

The composition may comprise metals selected from the group consisting of aluminum, brass, bronze and copper. The composition may be semi-metallic. By semi-metallic it is meant that a portion, ranging from a trace to a substantial amount of the composition is metal, but that it is only one component of the composition, which may comprise one or more other components.

In another aspect of the invention the composition is housed in a recess in the face.

In another aspect of the invention the recess extends substantially from the apical end to the basal end.

In another aspect of the invention the recess terminates in a tab at the apical end and a tab at the basal end.

In another aspect of the invention the composition has a co-efficient of friction in the range of 0.35-0.55.

In another aspect of the invention the co-efficient of friction is in the range of 0.45-0.55.

In another aspect of the invention the co-efficient of friction is about 0.46.

In another aspect of the invention the composition is affixed with an adhesive.

In another aspect of the invention the semi-metallic composition is additionally mechanically affixed.

In another aspect of the invention, an improved camming device is provided that has a superior range of operation, is lighter and has lower internal compressive forces. A camming device is for use as protection in cracks during rock climbing, and comprises at least one pair of lobes, one axle per pair of lobes, a stem, a loop and a release mechanism. The lobes comprise: a face having a contact area; an inside edge; an apical end; and a basal end, to define an inner surface and an outer surface. The improvement comprises a semi-a composition having a co-efficient of friction ranging between 0.35-0.55 affixed to the contact area.

In another aspect of the invention the composition is housed in a recess in the face.

In another aspect of the invention the recess extends substantially from the apical end to the basal end

In another aspect of the invention the recess terminates in a tab at the apical end and a tab at the basal end.

In another aspect of the invention the co-efficient of friction is in the range of 0.45-0.55.

In another aspect of the invention the co-efficient of friction is about 0.46.

In another aspect of the invention, the composition is comprised of a metal selected from the group consisting of aluminum, copper, bronze and brass.

In another aspect of the invention, the composition is a semi-metallic composition.

In another aspect of the invention the composition is affixed with an adhesive.

In another aspect of the invention the composition is additionally mechanically affixed.

In yet another aspect of the invention, an improved method of fall protection cracks during rock climbing is provided. The method comprises employing a camming device having a maximum range of about 0.9″-1.18″.

In another aspect of the invention the maximum range is about 1.0″-1.18″.

In another aspect of the invention the camming device has a co-efficient of friction on a contact area between 0.45 and 0.50.

In another aspect of the invention the camming device has a co-efficient of friction of about 0.46.

In another aspect of the invention, a rack of climbing cams is provided having five camming devices providing an operational range of approximately 4.0 inches.

In another aspect of the invention, the rack comprises four camming devices providing an operational range of approximately 2.6 inches.

In another aspect of the invention, the rack comprises three camming devices providing an operational range of approximately 1.7 inches.

In another aspect of the invention, the camming device has two axles and two pairs of lobes.

In another aspect of the invention, the loop comprises a composite cord.

In another aspect of the invention, a method of manufacturing an improved a camming device is provided. The camming device is comprised of at least one pair of lobes, one axle per pair of lobes, a stem, a loop and a release mechanism, the lobes comprising: a face having a contact area; an inside edge; an apical end; and a basal end, to define an inner surface and an outer surface. The method comprises increasing the static co-efficient of friction on a contact area by affixing a semi-metallic composition to the contact area.

In another aspect of the method, the semi-metallic composition is housed in a recess in the face.

In another aspect of the method, the recess extends substantially from the apical end to the basal end.

In another aspect of the method, the recess terminates in a tab at the apical end and a tab at the basal end.

In another aspect of the method the semi-metallic composition has a co-efficient of friction is in the range of 0.35-0.55.

In another aspect of the method the semi-metallic composition has a co-efficient of friction is in the range of 0.45-0.55.

In another aspect of the method the semi-metallic composition has a co-efficient of friction of about 0.46.

In another aspect of the method the semi-metallic composition is affixed with an adhesive.

In another aspect of the method the semi-metallic composition is additionally mechanically affixed.

In another aspect of the invention, the method further comprises utilizing a suitably selected composite cord for manufacture of the loop.

In another aspect of the invention, a method of manufacturing an improved a camming device is provided. The camming device is comprised of at least one pair of lobes, one axle per pair of lobes, a stem, a loop and a release mechanism, the lobes comprising: a face having a contact area; an inside edge; an apical end; and a basal end, to define an inner surface and an outer surface. The method comprises increasing the static co-efficient of friction on a contact area by affixing a composition having a co-efficient of friction in the range of 0.40-0.55 to the contact area.

In another aspect of the method, the composition is housed in a recess in the face.

In another aspect of the method, the recess extends substantially from the apical end to the basal end.

In another aspect of the method, the recess terminates in a tab at the apical end and a tab at the basal end.

In another aspect of the method the composition has a co-efficient of friction is in the range of 0.35-0.55.

In another aspect of the method the composition has a co-efficient of friction is in the range of 0.45-0.55.

In another aspect of the method the composition has a co-efficient of friction of about 0.46.

In another aspect of the method the composition is affixed with an adhesive.

In another aspect of the method the composition is additionally mechanically affixed.

In another aspect of the invention, the method further comprises utilizing a suitably selected composite cord for manufacture of the loop.

FIGURES

FIG. 1 is a perspective view of a camming device in accordance with an embodiment of the invention.

FIG. 2 is an exploded view of the camming device of FIG. 1.

FIG. 3A and B are drawings of the radius of the extended and contracted camming device of FIG. 1.

FIG. 4 is a perspective view of a lobe of the camming device of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

A camming device for climbing, generally referred to as 10, is shown in FIG. 1. The camming device 10 has two cams 12 in parallel relation to each other, each comprising two lobes, an inner lobe 14 and an outer lobe 16, for engaging a crack when actuated. The lobes 14, 16 are aluminum. The two cams 12 are rotatably mounted on a stainless steel axle 18, by means of a bore 20, such that inner lobes 14 oppose one another and the outer lobes 16 oppose one another as shown in FIG. 2. The lobes 14, 16 define a radius that expands as the camming device 12 is actuated, as shown in FIG. 3A and B. Each lobe 14, 16 is generally triangular and has a face 22, and an inside edge 24 terminating at an apical end 26, and a basal end 28 opposing the apical end 26 as shown in FIG. 4. An inner surface 30 and outer surface 32 are defined by the face 22, edge 24 and ends 26, 28. The face 22 has a logarithmic contact shape, with the contact area 34 comprising a semi-metallic composition. The semi-metallic composition is brake pad material, having a static coefficient of friction of about 0.46 when contacted with rock. The semi-metallic composition on the contact area 34 is affixed using adhesive and is housed in a recess 36 of the lobe 14, 16 with tabs 38, 40 extending from the apical end 26 of the lobe 14, 16 and the basal end 28, of the lobe 14, 16 as shown in FIG. 4. The semi-metallic composition increases holding power, allows for an increased operational range and lowers internal compressive forces. A stop 42 subtends the recess 36 in the vicinity of the basal end 28 and protrudes from the inner surface 30 of the outer lobe 16 and the outer surface 32 of the inner lobe 14, such that the stop 42 of one lobe 14 abuts the basal end 28 of the other lobe 16, when the camming device 10 is fully retracted. In this position, the camming device 10 may function as passive protection.

The axle 18 is retained in the bore 20 of the lobes 14, 16, by means of a hub 44 on either end 46 of the axle 18. Between the pairs of cams 12, a stem 48 comprising a composite cord made of Parallay™ construction HMPE fibre is rotatably mounted on the axle 18. A washer 47 is located on the axle 18 between the stem 48 and each inner lobe 14. A loop 50 is affixed to a distal end 52 of the stem 48 by splicing. A guide, 51, is rotatably mounted on the axle 18 and accepts the stem 48.

A release mechanism 56 is slidably mounted on the stem 48 by a plate 58 with a centrally located release bore 60, through which the stem 48 slides. Adjacent the release bore 60 on either side of the release bore 60 are a pair of bores 64 through which a resilient member, such as a cable 66 is threaded. The cable 66 is aligned such that the distance between the two lobes 14, 16 and the plate 58 is the same. Each lobe 14, 16 has an aperture 54 to accept the cable 66. The aperture 54 on the outer lobe 16 is on the outer surface 32 and the aperture 54 on the inner lobe 14 is also on the outer surface 32. The cable 66 of the release mechanism 56 is rotatably within the aperture 54.

The lobes 14, 16 are biased from one another in a cam 12 by biasing means, such as a spring 68. Hence, when downward pressure is exerted on the camming device 10, the cams 12 spring open into an actuated position, in which the face 22 with its contacting surface 34, engages a crack by abutting opposing rock walls of the crack. When the climber wants to release the camming device 10 from the crack, he pulls the plate 58 of the release mechanism 56 away from the rock while pushing the stem 48 in towards the rock, and the camming device 10 is released. The camming device 10 is then returned to a rack of camming devices.

EXAMPLE 1

Detailed friction testing of five advanced composite friction materials against 8 different types of rock, laboratory testing of twelve different two-part adhesives (including expoxies, acrylics and urethanes) for break away and internal strength and extensive research into new market products, in terms of cords, heat shrink tubing and metal based putties was carried out. This led to inventing a camming device with an 81.3% increase in the standard working range and a 34.5% reduction in stem weight. TABLE 1 Friction Material Testing Co-Efficient of Friction (μ) (Frictional Force/Normal Force) AFT- AFT- Al- F4-3- Friction Materials HF-61 9010 1006 200 6106 252 Rock Types Black Sandstone 0.38 0.58 0.45 0.35 0.48 0.38 Green Sandstone 0.48 0.41 0.62 0.53 0.53 0.64 Yellow Quartzite 0.59 0.62 0.62 0.55 0.52 0.55 Pink Quartzite 0.63 0.61 0.66 0.06 0.42 0.58 Gneiss 0.53 0.66 0.56 0.47 0.42 0.46 Basalt 0.33 0.55 0.33 0.39 0.34 0.45 Limestone 0.43 0.55 0.27 0.39 0.36 0.23 White Granite 0.67 0.67 0.51 0.54 0.45 0.43 Average Co-Efficient 0.51 0.58 0.50 0.41 0.44 0.47 of Friction Claimed Co-Efficient 0.61 0.46 0.52 0.42 0.31 0.41 of Friction Corrected Test Values 0.36 0.41 0.35 0.29 0.31 0.33

The introduction of a high frictional co-efficient material to the rock/lobe interface increases the frictional forces of the cam. This increased holding power allows for an increased operational range and lower internal compressive forces. The operational ranges for a set of cams of the present invention is shown in Table 3. The increase in range for #6 Trango cam is 0.35″ this corresponds to a 49.3% increase. The increase in range for a #7 Trango cam=1.36″ which translates to an 81.3% increase. TABLE 3 Cam operational ranges Cam Trango Improved cam #6 1.38 to 2.09 1.56 to 2.62 #7 1.89 to 2.64 2.60 to 3.96 #8 2.40 to 3.58 *All in inches*

The lobe shape of the cam is a logarithmic spiral defined as: r=e^(cθ)

-   -   Where: r=radius of spiral         -   e=natural logarithm         -   c=coefficient defining how fast the spiral opens         -   θ=angle measured in radians

The coefficient c, in equation (1) is limited by the coefficient of friction between the rock and the lobe interface. The claimed 0.42 coefficient of friction for material 9010 was used for the coefficient c in the lobe shape equation. Trango™ #7 (size 7 in Trango's range of cams) cam was used in the prototype model of the camming device, so the lobe size coefficient which factors the lobe equation to determine size is 0.515. This coefficient ensures that the vertical distance from the axle to the lobe surface is 1.00″, the distance for Trango cams. FIGS. 3A and B show an extended and a contracted cam lobe, demonstrating the range dimensions of the lobes for extended and contracted positions, respectively. The specified range of Trango's #7 Flex cam is 1.89″ to 2.64″ for a maximum range of about 0.75″. As shown in FIGS. 3A and B, the improved range is 2.60″ to 3.96″ for a maximum range of about 1.36″. The range of the improved camming devices of the present invention are shown relative to Trango camming devices. It can be seen from Table 3 that the range of the camming devices are significantly greater and hence, fewer camming devices are needed to cover the range of sizes. As would be known to one skilled in the art, the range is determined from a logarithmic equation, hence the percentage change in range will be exponential. For example, after detailing another cam of Trango's (the #6), the range increase was found to be 49.3%. This reduces the number of camming devices needed for a given rack. TABLE 2 Adhesives Evaluated Product Item Batch Number Number Number Product Description 326/7649 32629/ 2IP228B/ 18,000 cP, amber, two-part no-mix 38402 3IV8700D urethane methacrylate acrylic adhesive. E-05CL 29299 3I29723A 1,900/2,800 cP, ultra clear, 5 minute work life, two-part mercaptan epoxy. U-05FL 29348 3AZ9618A 640/35,000 cP, off white, 5 minute work life, two-part polyurethane adhesive.

The foregoing is a description of an embodiment of the invention. As would be known to one skilled in the art, there can be variations in design of the camming device that do not change the scope of the invention. For example, the camming device can be a single cam or double cam device. The plate of the release mechanism may be machined or forged metal, or may be injection moulded and comprise a polymeric material. The stops may be contoured flush with the face of the lobe. The composite cord can be comprised of, for example, but limited to non-metallic advanced climbing or sailing materials and can be spliced, knotted, sewn, glued, or mechanically fastened to form a loop. The cord is the main tensile load bearing member of the camming device. Suitable materials and means of fastening would be known to one skilled in the art. A protective sheath can surround the loop in the stem. The semi-metallic composition may be affixed to the face of the lobe by mechanical means or by a combination of mechanical and adhesive means. Further, a ceramic composition might replace the semi-metallic composition, and this would alter the coefficient of friction accordingly. Still further, the semi-metallic composition can be replaced with soft metals, such as, but not limited to Aluminum 5052 and 3003, coppers, brasses, and bronzes, that have a co-efficient of friction of about 0.35 and higher. The coefficient of friction can range from about 0.35-0.55. These and other modifications are within the scope of the invention. 

1. In a camming device for use as protection in cracks during rock climbing, comprising at least one pair of lobes, one axle per pair of lobes, a stem, a loop and a release mechanism, said lobes comprising: a face having a contact area; an inside edge; an apical end; and a basal end, to define an inner surface and an outer surface, wherein the improvement comprises: a composition comprising at least one metal affixed to said contact area.
 2. The camming device of claim 1 wherein said composition is housed in a recess in said face.
 3. The camming device of claim 2 wherein said recess extends substantially from said apical end to said basal end.
 4. The camming device of claim 3 wherein said recess terminates in a tab at said apical end and a tab at said basal end.
 5. The camming device of claim 4 wherein said composition has a co-efficient of friction in the range of 0.35-0.55.
 6. The camming device of claim 5 wherein the co-efficient of friction is in the range of 0.45-0.55.
 7. The camming device of claim 1 wherein the composition comprises metal selected from the group consisting of aluminum, copper, bronze and brass.
 8. The camming device of claim 4 wherein said composition is affixed with an adhesive.
 9. The camming device of claim 8 wherein said composition is additionally mechanically affixed.
 10. In a camming device for use as protection in cracks during rock climbing, comprising at least one pair of lobes, one axle per pair of lobes, a stem, a loop and a release mechanism, said lobes comprising: a face having a contact area; an inside edge; an apical end; and a basal end, to define an inner surface and an outer surface, wherein the improvement comprises: a composition having a co-efficient of friction ranging between 0.35-0.55 affixed to said contact area.
 11. The camming device of claim 10 wherein said composition is housed in a recess in said face.
 12. The camming device of claim 11 wherein said recess extends substantially from said apical end to said basal end.
 13. The camming device of claim 12 wherein said recess terminates in a tab at said apical end and a tab at said basal end.
 14. The camming device of claim 13 wherein the composition is a semi-metallic composition.
 15. The camming device of claim 13 wherein the composition comprises a metal selected from the group consisting of aluminum, brass, bronze and copper.
 16. The camming device of claim 15 wherein said composition is affixed with an adhesive.
 17. The camming device of claim 16 wherein said composition is additionally mechanically affixed.
 18. In a rack of camming devices, for use as protection in cracks during rock climbing, wherein each camming device in the rack comprises at least one pair of lobes, one axle per pair of lobes, a stem, a loop and a release mechanism, said lobes comprising: a face having a contact area; an inside edge; an apical end; and a basal end, to define an inner surface and an outer surface, wherein the improvement comprises: five camming devices providing an operational range of approximately 4.0 inches.
 19. The rack of camming devices of claim 18 wherein the improvement comprises four camming devices providing an operational range of approximately 2.6 inches.
 20. The camming device of claim 1 wherein there are two pairs of lobes and two axles.
 21. The camming device of claim 10 wherein there are two pairs of lobes and two axles.
 22. The camming device of claim 1 wherein there is one pair of lobes and one axle.
 23. The camming device of claim 10 wherein there is one pair of lobes and one axle. 